Reports suggested the confrontation had been sparked by an earlier run-in Lobov had with UFC lightweight title contender Nurmagomedov - who was on the targeted bus.

The ugly scenes were condemned by UFC president Dana White, who labelled them "one of the most disgusting things that's happened in the history of the company".

McGregor has been a divisive presence in the sport due to his quick temper, flashy tastes and trash-talking of rivals, but quickly became one of UFC's most bankable stars after signing a contract in 2013.